This invention relates to a motion sensing device and in particular to a device for sensing rotation of a wheel.
With large multi-wheeled vehicles such as tractor-trailers it is important to know when any of the wheels stop rotating. In the absence of a motion sensor the driver of the vehicle has no way of knowing when a wheel locks, for example because of bearing failure.
The patent art includes many examples of motion sensing devices and more specifically motion sensing devices which rely on centrifugal force. Examples of motion sensing devices are found in U.S. Pat. No. 3,435,164 issued to D. de Perczel on Mar. 25, 1969; U.S. Pat. No. 3,619,524 issued to A. G. Gillund on Nov. 9, 1971; U.S. Pat. No. 3,646,543 issued to J. D. Morris on Feb. 29, 1972; U.S. Pat. No. 3,763,484 issued to W. L. Byers on Oct. 2, 1973; U.S Pat. No. 3,812,308 issued to L. E. Bell et al on May 21, 1974; U.S. Pat. No. 3,927,286 issued to A. Fohl on Dec. 16, 1975 and U.S. Pat. No. 4,196,429 issued to C. H. Davis on Apr. 1, 1980. Many of the devices disclosed by the above identified patents are unsuitable for sensing wheel rotation and others of the devices are unnecessarily complicated.
Thus, in spite of the large numbers of patents for such devices, there still exists a need for a simple yet effective device for sensing rotation of a wheel. The object of the present invention is to to meet such need, at least partially, by providing a relatively simple, effective device for sensing wheel rotation.